What is OSI model ?
Ans- The OSI (Open Systems Interconnection) model is a conceptual framework used to understand and standardize the functions of a telecommunications or computing system without regard to its underlying internal structure and technology. It was developed by the International Organization for Standardization (ISO) in 1984.
The OSI model consists of seven layers, each with specific functions and responsibilities:
1. *Physical Layer (Layer 1)*: Defines the physical means of transmitting data between devices (e.g., cables, Wi-Fi).
2. *Data Link Layer (Layer 2)*: Ensures error-free transfer of data frames between two devices on the same network.
3. *Network Layer (Layer 3)*: Routes data between different networks, using logical addresses (IP addresses).
4. *Transport Layer (Layer 4)*: Provides reliable data transfer between devices, using protocols like TCP and UDP.
5. *Session Layer (Layer 5)*: Establishes, manages, and terminates connections between applications.
6. *Presentation Layer (Layer 6)*: Converts data into a format that can be understood by the receiving device.
7. *Application Layer (Layer 7)*: Supports functions like email, file transfer, and web browsing.
The OSI model helps network engineers and developers:
- Understand how data is transmitted over networks
- Troubleshoot issues by identifying which layer is causing the problem
- Develop compatible network devices and protocols
While the OSI model is not directly implemented in modern networks, it remains a fundamental concept in understanding network architecture and communication.
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